An ad hoc wireless network (a mesh network) is a self-organizing network in which the network devices themselves establish communication links with one another. Wireless networks may be used in different settings. For example, a wireless network may be established between monitoring and control devices and a host computer.
In one example, network devices monitor and control electrical systems, such as a building lighting system or fire alarm system. The devices report status information from their monitored system to the host computer. In response, the host computer sends control commands, which the devices use to control the electrical systems.
There are numerous issues involved in establishing and maintaining a wireless network, including power consumption and network congestion. Network devices on a wireless network typically run off of batteries, which must be checked and changed periodically. Changing batteries frequently can be inconvenient. Furthermore, as wireless networks become larger, the amount of data transmitted across those networks increases, which can result in data packet collision and, thus, degraded quality of service (QoS).
Nodes (e.g., devices) on a wireless network may communicate using a process known as frequency hopping. Frequency hopping allows nodes to communicate using different frequency channels. Nodes on the network typically cycle through different frequency channels, during which communications can be sent to, and received from, other nodes. When not communicating, the nodes typically enter a low-power state in order to save power. Heretofore, frequency hopping on a mesh network was implemented by synchronizing all devices of the network. That is, each device followed the same frequency sequence, and entered its communication mode at the same time and for the same duration. This configuration has proven difficult to maintain, particularly for large networks.